Norwegian Air, Europe's third-biggest budget airline after Ryanair and EasyJet, launched long-haul operations this year and hoped to capitalize on the Dreamliner's lower operating costs.

But during the autumn its first two Dreamliners broke down more than half a dozen times, forcing it to lease back-up planes at short notice or cancel flights. Since then the airline has added a third Dreamliner to its fleet.

Last week Norwegian Air said it would buy two more 787-9 Dreamliners, seeing the aircraft's technical advances as outweighing its operating problems as the budget carrier expands in long-haul services.